Gene therapy techniques used in treating diseases, such as tumors, have increasingly drawn attentions and concerns of a large number of researchers. Gene therapy means transfecting some functional genetic materials, including siRNA, mRNA, miRNA, DNA, nucleic acid aptamers and promoter region sequences of cancer genes, into cells and expressing them in the cells to ultimately treat diseases. A key factor of gene therapy is to transfect therapeutic genes into cells by using safe and efficient vectors. Generally, viral vectors such as RNA viruses or DNA viruses, or non-viral vectors such as calcium phosphate precipitation, lipofection or microinjection and the like, are used to transfect therapeutic genes (H. Yin, R. L. Kanasty, A. A. Eltoukhy, A. J. Vegas, J. R. Dorkin, D. G. Anderson, Non-viral vectors for gene-based therapy, Nature Rev., 15, 541-555, 2014; Viktoriya Sokolova and Matthias Epple, Inorganic Nanoparticles as Carriers of Nucleic Acids into Cells, Angew. Chem. Int. Ed. 2008, 47, 1382-1395; S. Huo, S. Jin, X. Ma, X. Xue, K. Yang, A. Kumar, P. C. Wang, J. Zhang, Z. Hu, X.-J. Liang, Ultrasmall gold nano particles as carriers for nucleus-based gene therapy due to size-dependent nuclear entry, ACS NANO, 8(6), 5852-5862, 2014). However, due to their defects and deficiencies, clinical uses of these methods are still greatly limited.
In recent years, the study of using ruthenium (II) complexes as gene vectors has aroused widespread interests of many researchers. Kumbhar et al reported an application of ruthenium polypyridine complexes as gene vectors (S. S. Bhat, A. S. Kumbhar, A. K. Kumbhar, A. Khan, P. Lonnecke, Ruthenium(II) polypyridyl complexes as carriers for DNA delivery, Chem. Comm, 2011, 47, 11068-1070); Chao Hui et al reported a method of using ruthenium (II) polypyridyl complexes as gene vectors ( ). However, the ruthenium complexes used in these reports have relatively large molecular weight with relatively complicated synthesis processes, and have limited effects when used as gene vectors. Additionally, none of the above reports on ruthenium complexes and their optical isomers related to their use as gene vectors of target cell nucleuses. Replication and transcription of genes mainly takes place in cell nucleuses and the efficiency of self-replication and transcription of genes can be improved by nucleic acid-targeted delivery to cell nucleuses, thereby obtaining better therapeutic effects.